Yohimbine hydrochloride
[CAS# 65-19-0]

Identification

• Classification: API >> Nervous system medication >> Antidepressant, manic
• Name: Yohimbine hydrochloride
• Synonyms: 17-Hydroxy-yohimban-16-carboxylic acid methyl ester hydrochloride
• Molecular Formula: C₂₁H₂₆N₂O₃.HCl
• Molecular Weight: 390.91
• CAS Registry Number: 65-19-0
• EC Number: 200-600-4
• SMILES: COC(=O)[C@H]1[C@H](CC[C@@H]2[C@@H]1C[C@H]3C4=C(CCN3C2)C5=CC=CC=C5N4)O.Cl

Properties

• Melting point: 288 - 290 °C (Decomposes) (Expl.)
• Solubility: H2O: 10 mg/mL, DMSO: 20 mM (Expl.)
• Alpha: 99 ° (c=1%, H2O, dry subst) (Expl.)

Safety Data

• Hazard Symbols: GHS06 Danger
• Risk Statements: H300-H301-H311-H331
• Safety Statements: P261-P262-P264-P270-P271-P280-P301+P316-P302+P352-P304+P340-P316-P321-P330-P361+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	3	H331
Acute toxicity	Acute Tox.	3	H311
Acute toxicity	Acute Tox.	2	H300
Acute toxicity	Acute Tox.	3	H301
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Acute toxicity	Acute Tox.	2	H330
Acute toxicity	Acute Tox.	1	H300
Specific target organ toxicity - repeated exposure	STOT RE	2	H373

Discovery and Applications

Yohimbine hydrochloride is the hydrochloride salt form of yohimbine, an indole alkaloid derived primarily from the bark of the Pausinystalia yohimbe tree, native to West Africa. Yohimbine has a long history of traditional use as an aphrodisiac and stimulant, and its hydrochloride form improves its solubility and stability for pharmaceutical use.

The discovery of yohimbine dates back to the 19th century, when the compound was first isolated from the bark of the yohimbe tree. Subsequent research identified yohimbine as an alpha-2 adrenergic receptor antagonist, a property that underpins many of its pharmacological effects. Yohimbine hydrochloride acts primarily by blocking presynaptic alpha-2 adrenergic receptors, leading to increased release of norepinephrine and enhanced sympathetic nervous system activity.

Clinically, yohimbine hydrochloride has been used to treat erectile dysfunction and other sexual disorders, due to its ability to increase blood flow and nerve impulses in genital tissues. It has also been studied for its potential to aid weight loss by promoting lipolysis and increasing energy expenditure. However, its therapeutic use is limited by side effects such as increased heart rate, elevated blood pressure, anxiety, and gastrointestinal disturbances.

Beyond its sexual health applications, yohimbine hydrochloride has been explored in psychiatric and neurological research. It may influence mood and anxiety by modulating noradrenergic pathways. Some studies have investigated its use in managing orthostatic hypotension and in enhancing athletic performance, although evidence remains inconclusive.

In pharmaceutical preparations, yohimbine hydrochloride is administered in oral tablet form or as an injectable solution. Dosage and safety profiles vary, requiring careful medical supervision due to the risk of adverse cardiovascular and neurological effects. The compound’s pharmacokinetics include rapid absorption, hepatic metabolism, and renal excretion.

Yohimbine hydrochloride remains a compound of interest for its unique mechanism of action and diverse biological effects. Research continues into optimizing its clinical applications and minimizing side effects. Regulatory status varies by country, with some regions restricting its use to prescription-only medications, while others limit or ban its availability due to safety concerns.

References

1990. Structure-activity relationship of yohimbine and its related analogs in blocking alpha-1 and alpha-2 adrenoceptors: A comparative study of cardiovascular activities. Chemical and Pharmaceutical Bulletin, 38(6).
DOI: 10.1248/cpb.38.1702

1990. Identification of human platelet a2-adrenoceptors with a new antagonist [3H]-RX821002, a 2-methoxy derivative of idazoxan. British Journal of Pharmacology, 100(4).
DOI: 10.1111/j.1476-5381.1990.tb14105.x

1979. Blockade of the sodium channels of the node of Ranvier membrane channels by the alkaloid yohimbine. Doklady Akademii nauk SSSR.
URL: https://pubmed.ncbi.nlm.nih.gov/487935